There are many advantages to having your boat in an LLC, S corporation, or a Schedule C as long as you attempt to use it as a business. Nothing says you have to turn a profit!
Actually, according to my CPA that is not true.
I paid her to discuss legal ways to tax advantage the boat, IE "write off" either the boat itself, or its expenses.
Understand that I also have a fully functional profit making corporation that my admrial and I own, so we had several different avenues to explore.
There are a couple of ways to legally tax advantage a boat, but if you do not make a profit in a reasonable time frame then you're flagging yourself for an audit, and the IRS can and will dissallow expenses claiming that the business is a hobby.
First way would be to charter the boat out. You buy a boat and make a good faith effort to turn it into a charter business. You as a person are a customer of that business and pay the business for use of the boat. You could take the boat out on "maintenance cruises" a couple times a year and actually write off those expenses as well.
The problem is chartering requires a licensed captain, or letting someone bareboat the boat. It requires marketing, and all the things that make a business a real business.
If you do not make a profit then after a very few years the IRS will dissallow the "business loss" against your personal income.
The next way would be to use the boat to entertain clients and even employees. My accountant warned me strongly against this. If I had a larger business than ours she said it could become justifiable but not for us.
Another way would be to actually use the boat as part of the business. Both of my neighbors businesses own their private aircraft, and they use them as part of their construction businesses. My business is a wholesale electrical distributor so that will not work for me.
The ONLY audit defendable thing we figured out we could do was to add a satellite communications system to the boat so that I would be able to operate my business from the boat. We did that with the business purchacing the sat com gear and paying the subscription service fees. I actually use the sat com link for business functions while on the boat, so it is a justifiable expense, just like any other telecommuter setup.